| 1. |
- Buss, Wolfram, et al.
(författare)
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Synergies between BECCS and Biochar-Maximizing Carbon Sequestration Potential by Recycling Wood Ash
- 2019
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 7:4, s. 4204-4209
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Tidskriftsartikel (refereegranskat)abstract
- Bioenergy carbon capture and storage (BECCS) and biochar are key carbon-negative technologies. In this study, synergies between these technologies were explored by using ash from wood combustion, a byproduct from BECCS, as an additive (0, 5, 10, 20, and 50 wt %) in biochar production (wood pyrolysis at 450 degrees C). The addition of wood ash catalyzed biochar formation and increased the yield of fixed carbon (FC) (per dry, ash-free feedstock), i.e., the sequestrable carbon per spruce wood input. At the highest ash addition (50%), 45% less wood was needed to yield the same amount of FC. Since the land area available for growing biomass is becoming scarcer, our approach significantly increases biochar's potential to sequester carbon. However, increasing the feedstock ash content results in less feedstock carbon available for conversion into FC. Consequently, the yield of FC per pyrolysis run (based on dry feedstock) in the 50% ash-amended material was lower than in the control. An economic analysis showed that the 20% ash-amended biochar brings the biggest cost savings over the control with a 15% decrease in CO2-abatement costs. Biochar-ash composites increase the carbon sequestration potential of biochar significantly, reduce the CO2-abatement costs, and recycle nutrients which can result in increased plant growth in turn and more biomass for BECCS, bringing synergies for BECCS and biochar deployment.
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| 2. |
- Buss, Wolfram, et al.
(författare)
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Unexplored potential of novel biochar-ash composites for use as organo-mineral fertilizers
- 2019
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Ingår i: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 208, s. 960-967
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Tidskriftsartikel (refereegranskat)abstract
- Application of wood ash on forest and agricultural soils can provide nutrients and increase soil pH, however, it changes the soil chemistry rapidly and temporarily, often resulting in reduced plant growth and potassium leaching. Biochar from woody materials are nutrient poor and need nutrient enhancement prior to soil application. In this study, spruce residues were mixed with spruce/pine ash in different ratios (0–50%) to produce biochar-ash composites at 450 °C. The biochar yield (ash-free basis) increased by 80–90% with the addition of 50% ash due to catalytic biochar formation. Consequently, nearly half the amount of wood is needed to produce the same amount of (ash-free) biochar. Mineral release was moderated in the composites compared to pure ash, demonstrated by a lower electric conductivity and % available K content (a factor of 2.5–4.4 lower than in wood ash). Furthermore, the % available chromium content, which is a key potentially toxic element in wood ash, decreased by a factor of 50–160. Soil application of biochar-ash composites decreases the risk of Cr toxicity, salinity stress and leaching of K in soil substantially compared to ash application. Biochar-ash composites are a novel product with vast unexplored potential for use in forestry and agriculture.
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| 3. |
- Kozyatnyk, Ivan, 1982-, et al.
(författare)
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Removal of contaminants of emerging concern from multicomponent systems using carbon dioxide activated biochar from lignocellulosic feedstocks
- 2021
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Ingår i: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 340
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Tidskriftsartikel (refereegranskat)abstract
- Adsorption of six contaminants of emerging concern (CECs) – caffeine, chloramphenicol, carbamazepine, bisphenol A, diclofenac, and triclosan – from a multicomponent solution was studied using activated biochars obtained from three lignocellulosic feedstocks: wheat straw, softwood, and peach stones. Structural parameters related to the porosity and ash content of activated biochar and the hydrophobic properties of the CECs were found to influence the adsorption efficiency. For straw and softwood biochar, activation resulted in a more developed mesoporosity, whereas activation of peach stone biochar increased only the microporosity. The most hydrophilic CECs studied, caffeine and chloramphenicol, displayed the highest adsorption (22.8 and 11.3 mg g−1) onto activated wheat straw biochar which had the highest ash content of the studied adsorbents (20 wt%). Adsorption of bisphenol A and triclosan, both relatively hydrophobic substances, was highest (31.6 and 30.2 mg g−1) onto activated biochar from softwood, which displayed a well-developed mesoporosity and low ash content.
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| 4. |
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| 5. |
- Phounglamcheik, Aekjuthon, 1989-
(författare)
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Biocarbon for fossil coal replacement
- 2018
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This research aims to provide a full view of knowledge in charcoal production for fossil coal replacement. Charcoal from biomass is a promising material to replace fossil coal, which is using as heating source or reactant in the industrial sector. Nowadays, charcoal with quality comparable to fossil coal is produced by high-temperature pyrolysis, but efficiency of the production is relatively low due to the trade-off between charcoal property and yield by pyrolysis temperature. Increasing charcoal yield by means of secondary char formation in pyrolysis of large wood particles is the primary method considering in this work. This research has explored increasing efficiency of charcoal production by bio-oil recycling and CO2 purging. These proposed techniques significantly increase concentration and extend residence time of volatiles inside particle of woodchip resulting extra charcoal. Characterization of charcoals implies negligible effect of these methods on charcoal properties such as elemental composition, heating value, morphological structure, and chemical structure. Besides, reactivity of charcoal slightly increased when these methods were applied. A numerical model of pyrolysis in a rotary kiln reactor has been developed to study the effect of design parameters and conditions in reactor scale. The simulation results showed fair prediction of temperature profiles and products distribution along the reactor length. Nonetheless, to deliver full knowledge in charcoal production, further works are planned to be done at the end of this doctoral research.
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| 6. |
- Sun, Jiacheng, et al.
(författare)
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Synergistic valorisation of wastewater microalgae : Sulphuric acid-assisted phosphorus recovery and enhanced electrochemical performance of biochar for supercapacitors
- 2024
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Ingår i: Chemical Engineering Journal. - : Elsevier B.V.. - 1385-8947 .- 1873-3212. ; 494
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Tidskriftsartikel (refereegranskat)abstract
- This study proposes a strategy for phosphorus recovery from algae biomass while simultaneously enhancing the electrochemical capacitance of resulting biochar in supercapacitor applications. Use of sulphuric acid leaching process on both wastewater microalgae and seaweed biochar demonstrated high phosphorus recovery rates, ranging from 93.4% to 95.4%, while at the same time retaining 52.7% to 58.6% of Fe content in the biochars. By modifying the sequential order of leaching (L) and physical activation (A) as LA and AL, the strategy allows for the optimisation of phosphorus recovery and the electrochemical properties of activated biochars. During the LA process, a more porous structure formed and more S-containing functional groups occurred compared to AL which explained the higher specific capacitance (486.3F g−1 at a current density of 1 A g−1) of wastewater microalgae biocarbon with the LA process. Consequently, the life cycle assessment of this strategy revealed a significant global warming reduction potential of 1.34–2.94 tonnes of CO2-eq/yr for each tonne of biochar produced. This indicates that sulphuric acid-assisted biochar production could be a sustainable strategy for waste management and carbon sequestration, while simultaneously generating economic profits from valorised carbon material for energy storage applications.
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| 7. |
- Weidemann, Eva, et al.
(författare)
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Influence of pyrolysis temperature and production unit on formation of selected PAHs, oxy-PAHs, N-PACs, PCDDs, and PCDFs in biochar-a screening study
- 2018
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Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 25:4, s. 3933-3940
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Tidskriftsartikel (refereegranskat)abstract
- The influence of reactor type and operating conditions of the pyrolysis unit on the final concentration of toxic contaminants in biochar remains unclear. Therefore, we determined the concentrations of polycyclic aromatic hydrocarbons (PAHs), oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs), nitrogen-containing polycyclic aromatic compounds (N-PACs), polychlorinated dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs) in biochars produced from three different feedstocks (softwood, wheat straw, and anaerobic digestate). Different scaled pyrolysis units (one batch and two continuous units) at two different temperatures (550 and 700 degrees C) were considered. The results revealed that the type of biomass had a significant influence on the PAH, oxy-PAH, and N-PAC content of the biochars. The configuration and type of the pyrolysis unit influenced only the wheat straw pyrolyzed at 550 degrees C. PCDDs and PCDFs occurred at very low levels in the biochars. In terms of PAH, PCDD, and PCDF content, the biochars assessed in this study represent a low risk to the environment, regardless of the temperature and type and size of the pyrolysis unit.
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| 8. |
- Wurzer, Christian, et al.
(författare)
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Hydrothermal recycling of carbon absorbents loaded with emerging wastewater contaminants
- 2023
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Ingår i: Environmental Pollution. - : Elsevier. - 0269-7491 .- 1873-6424. ; 316
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Tidskriftsartikel (refereegranskat)abstract
- Adsorption using carbon materials is one of the most efficient techniques for removal of emerging contaminants such as pharmaceuticals from wastewater. However, high costs are a major hurdle for their large-scale application in areas currently under economic constraints. While most research focuses on decreasing the adsorbent price by increasing its capacity, treatment costs for exhausted adsorbents and their respective end-of-life scenarios are often neglected. Here, we assessed a novel technique for recycling of exhausted activated biochars based on hydrothermal treatment at temperatures of 160–320 °C. While a treatment temperature of 280 °C was sufficient to fully degrade all 10 evaluated pharmaceuticals in solution, when adsorbed on activated biochars certain compounds were shielded and could not be fully decomposed even at the highest treatment temperature tested. However, the use of engineered biochar doped with Fe-species successfully increased the treatment efficiency, resulting in full degradation of all 10 parent compounds at 320 °C. The proposed recycling technique showed a high carbon retention in biochar with only minor losses, making the treatment a viable candidate for environmentally sound recycling of biochars. Recycled biochars displayed potentially beneficial structural changes ranging from an increased mesoporosity to additional oxygen bearing functional groups, providing synergies for subsequent applications as part of a sequential biochar system.
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